I've been experimenting with glass and have come across some problems.  Here is part of a scene that I created using Moray and sPatch.  The texture used for both the sphere and shot glass is Glass1 from the glass material library that comes with Moray.  Whereas the sphere is normal looking, the shot glass has all those black inconsistencies.  There are walls covering all sides of the objects, so the black is not anything reflected or refracted.  When I take away the refraction of the shot glass, the inconsistencies disappear.  How do I get rid of those inconsistencies?
(By the way, the shot glass was created from a lathe in sPatch then exported to Moray)